Many homes in the United States and in other countries of the world have attic fans for improving ventilation. Attic fans are typically placed above an opening in a ceiling in a home and are electrically operated so that when turned "on", air is drawn from the interior of the room in which the fan is positioned and expelled through openings in the attic of the home. Attic fans work efficiently to produce cooling effect within a home. Thus, fresh and usually cooler air is drawn into the home and air is expelled out of the attic, cooling the attic. Since attic fans do not employ any type of refrigeration system, they are economical to operate and in some parts of the country are the only artificial cooling system required for homes.
One problem with attic fans however is that they require a rather large opening in the ceiling of the home in which they are used. This large opening provides the potential for great loss of heat during winter months when the attic fan is not employed. The typical closure of an attic fan, as employed in the United States and other areas, is a system consisting of a series of paralleled louvers. The louvers are balanced in such a way that when the attic fan is turned "on" and starts drawing air, the air causes the louvers to lift to an open position and air freely passes therethrough. When the attic fan is turned "off" and the passage of air therethrough terminates, the louvers fall back to an overlapping, closed position. This arrangement works automatically, however, louvers seldom fit tightly and closely to each other and are normally not formed of insulative type material. Thus, the typical attic fan louver closure system provides an area of great heat loss during winter months.
The purpose of this disclosure is to provide an improved closure for attic fans and particularly an improved closure for attic fans utilized in a home or other building which also includes an electrically operated heating system.
For background information relating to other devices for providing closures for attic fans or the like, see the following previously issued U.S. Pat. Nos. 2,096,503; 3,125,371; 3,130,719; 3,196,814; 3,669,041; 4,304,071 and 4,760,773.
These prior patents show various closure devices or switching apparatuses for use in conjunction with closures, but none show all of the features of the present invention for accomplishing improved energy efficiency in connection with the use of an attic fan.